Shocking scenes from 5 years ago of Lower Manhattan subways inundated by Superstorm Sandy's floodwaters speak volumes about how devastating storms can be to this flood-prone area of New York City.

But fast forward 5 years to Friday, as MTA officials unveiled an assortment of impressive technological steps to prevent similar havoc below ground.

At various entrances to the Whitehall Station, there are massive, submarine-like doors to keep water out. There are also huge metal flood logs that can be stacked like bricks above the steps.

At the South Ferry Station, a massive metal door can be closed to block rising water. And at the Canal Street stop, roll-out tarps can cover subway steps, able to withstand up to 14 feet of water.

All of this is part of a nearly $8 billion project to safeguard MTA facilities in future storms, strong enough for a category 2 or 3 hurricane. More than 100 subway entranceways now have special protections, in addition to 3,500 vents, grates and manholes, in many cases using special customized technology invented just for New York City.

There are also special contraptions for grates that will prevent water from pouring in and damaging sensitive, expensive underground equipment.

MTA officials said this equipment can be rolled quickly in the 24 hours before a storm is expected to strike.